| fungal fimbriae. i. structure, origin, and synthesis. | fine hair-like appendages on the cell walls of the another smut ustilago violacea are described. these hairs are termed fimbriae because of their close similarity to the fimbriae (pili) found on certain gram-negative bacteria. cells of u. violacea may carry more than 200 fimbriae varying in length from about 0.5 mum to over 10 mum, and having a diameter of about 60-70 a. some fimbriae produce knobs similar to those found on bacterial sex fimbriae. log-phase cells are the most densely fimbriated, ... | 1975 | 47260 |
| effect of chloramphenicol on the electron systems in ustilago cynodontis. | the mycelial cells of ustilago cynodontis possess at least two electron transport systems: a cyanide-sensitive cytochrome pathway, which represents the major route for electron transport, and an alternative cyanide-insensitive pathway, inhibited by salicylhydroxamic acid. in the presence of chloramphenicol in the culture medium, mycelial cells respire only by the alternatuve chain. the stable induced yeast-like cells, obtained by prolonged chloramphenicol treatment of the mycelial cells, respire ... | 1976 | 182673 |
| relationships between the correction of mismatched bases in dna and mutability. | | 1979 | 290445 |
| the recognition of mismatched base pairs in dna by dnase i from ustilago maydis. | the activity of ustilago maydis dnase i, an enzyme implicated in genetic recombination, on dna substrates containing unpaired or mismatched bases, was examined. the enzyme nicked supercoiled pm-2 molecules, converting these to relaxed circular and linear molecules. discrete double stranded linear fragments smaller than unit length were also observed after digestion at high enzyme concentration. heteroduplex molecules were constructed using phi80 bacteriophage derivatives which contained single b ... | 1978 | 353513 |
| mode of action of the azasteroid antibiotic 15-aza-24 methylene-d-homocholesta-8,14-dien-3 beta-ol in ustilago maydis. | ustilago maydis sporidia treated with 0.1 mug of azasterol (15-aza-24-methylene-d-homocholesta-8,14-dien-3beta-ol) per ml appeared branched and vacuolated after 6 h of incubation. sporidial multiplication, dry weight increase, and synthesis of protein, deoxyribonucleic acid, and ribonucleic acid were only slightly or moderately inhibited during the initial 3 h of incubation. an increase of free fatty acids was observed in lipid extracts of treated sporidia after incubation for 3 h or more. ergos ... | 1979 | 383015 |
| characterization of ustilago ribonuclease u2. effects of chemical modification at glutamic acid-61 and cystine-1 and of organic solvents on the enzymatic activity. | rnase u2 was purified and crystallized from the enriched culture medium (ammonium sulfate-urea-corn meal) of ustilago sphaerogena and its characteristics were investigated. chemical modification of rnase u2 was conducted with monoiodoacetic acid to carboxymethylate glu-61 and with 2-methoxy-5-nitrotropone to nitrotroponylate the amino terminal residue. the amino terminal residue was modified reversibly by this reagent. comparison of the 2'-amp binding in the modified enzyme and the native one sh ... | 1979 | 422534 |
| effects of miconazole and dodecylimidazole on sterol biosynthesis in ustilago maydis. | miconazole at minimal fungitoxic concentrations inhibits ergosterol biosynthesis in sporidia of ustilago maydis by interference with sterol c14 demethylation. the action is analogous to that of the fungicides triarimol and fenarimol. the fungicide 1-dodecylimidazole at low concentrations (0.1 to 0.25 mug/ml) inhibits sterol c14 demethylation; however, at higher concentrations (1.0 mug/ml or greater) it also inhibits 2,3-oxidosqualene cyclization and subsequent transmethylation. it is postulated ... | 1979 | 464593 |
| gunacin, a new quinone antibiotic from ustilago sp. | in a screening program for antibiotics which were antagonized by cysteine, a strain, which was characterized as ustilago sp., was found to produce a new quinone antibiotic, gunacin. the molecular weight m+ = 348.084 determined by mass spectroscopy, corresponds to a molecular formula of c17h16o8. further spectroscopic data prove that gunacin is a new antibiotic. the antibiotic possesses a good inhibitory effect against mycoplasmas and gram-positive bacteria including multi-resistant strains. it a ... | 1979 | 528380 |
| [newer antimycotics. iv. aryl-hydrazones of mesoxalic-acid-seminitril-hydrazid (author's transl)]. | the author produced a number of aryl-hydrazones of mesoxalic-acid-seminitril-hydrazide and their n2-acyl-derivatives, farther the halogeno-substituted phenyl-hydrazones of mesoxalic-acid-seminitril-hydrazones, and investigated their fungistatic efficiency in vitro. from the author's results it can be concluded, that 2-, 3- and 4-chloro-phenyl-hydrazones of mesoxalic-acid-siminitril-hydrazide exert a strong fungistatic effect on trichophyton- and epidermophyton-species, but they are inactive on o ... | 1978 | 566496 |
| aerobiological studies based in derby. ii. simultaneous pollen and spore sampling at eight sites within a 60 km radius. | in order to determine whether a sampling site in the centre of derby, where air sampling had been carried out for five summers, really provided valid aerobiological data for the surrounding area, eight identical volumetric spore traps were operated simultaneously during the summer of 1969 at various sites up to 56 km from derby. for most pollen and spore types, total numbers and seasonal pattern at all the sampling sites were found to be similar, although a few extreme and unexpected variations ... | 1978 | 568523 |
| further characterisation of a nucleic acid binding protein. | a glycoprotein which binds to nucleic acids has now been purified from ustilago maydis until free from detectable deoxyribonuclease activity. it binds to a variety of substrates and in doing so, makes them soluble in dilute trichloroacetic acid. physical studies suggest that it forms a variety of aggregates under low ionic strength, but at high ionic strength the monomer consists of a single polypeptide chain. preliminary experiments have detected this novel binding activity in bacterial, fungal ... | 1979 | 571603 |
| aerobiological studies based in derby. i. a simplified automatic volumetric spore trap. | a simplified version of the hirst automatic volumetric spore trap has been developed in derby for aerobiological studies. in comparative trials, the number of spores retained by the morrow brown trap were similar in the case of larger spores such as alternaria (102%), rather higher in the case of grass pollen (136%) and considerably higher (166--201%) for very small spores such as sporobolomyces and tilletiopsis. impaction efficiency has been improved by using a narrower slit. the trap designed ... | 1978 | 709802 |
| aerobiological studies based in derby. iii. a comparison of simultaneous pollen and spore counts from the east coast, midlands and west coast of england and wales. | the air spora of two sites on the east coast of britain and one on the west coast were compared with each other and with the regular sampling site in derby by the simultaneous operation of volumetric spore traps. concentrations of airborne spores and pollen were found to be usually less at the coastal sites than in derby. the effect of wind direction was shown to be important at coastal sites because daily counts often showed rises and falls corresponding to off- and on-shore winds respectively. ... | 1978 | 709803 |
| killer phenomenon in ustilago maydis: mapping viral functions. | | 1978 | 745596 |
| the genetic control of meiosis. | | 1976 | 797314 |
| nuclease that preferentially inactivates dna containing mismatched bases. | | 1975 | 810727 |
| differential activity staining: its use in characterization of guanylyl-specific ribonuclease in the genus ustilago. | guanylyl-specific ribonuclease can be identified by a novel technique employing electrophoresis in polyacrylamide slabs followed by differential activity staining. the technique requires as little as 7 ng of enzyme which may be grossly admixed with contaminants, including other ribonucleases. upon electrophoresis and activity staining, a variety of ribonucleases can be visualized as light or clear bands in a colored background formed by toluidine blue complexed with oligonucleotide substrate. gu ... | 1975 | 813217 |
| differential chromosomal and mitochondrial dna synthesis in temperature-sensitive mutants of ustilago maydis. | the amount and type of residual dna synthesis was determined in eight temperature-sensitive mutants of the smut fungus ustilago maydis after incubation at the restrictive temperature (32 degrees c) for eight hours. mutants ts-220, ts-207, ts-432 and ts-346 were found to have an overall reduction in the synthesis of both nuclear and mitochondrial dna comparison to the wild-type. in mutants ts-20, tsd 1-1, ts-84 and pol 1-1 nuclear dna synthesis was depressed relative to mitochondrial synthesis. t ... | 1977 | 834176 |
| genetic and cell cycle analysis of a smut fungus (ustilago violacea). | | 1977 | 875744 |
| virus-like particles in ustilago maydis: mutants with partial genomes. | mutants with partial genomes for the virus-like particles of u. maydis were recovered following treatment with nitrosoguanidine. examination of the properties retained by progeny of genetic crosses indicates that the 2.9 x 10(6) dalton component of double-stranded rna contains the information for capsid formation and dsrna replication. other components appear to contain the information for killer function and immunity to killer. the use of such mutants for studies on the evolution of viruses wit ... | 1977 | 892422 |
| induced mutagenesis in ustilago maydis. ii. an in vivo biochemical assay. | uv gamma radiation-induced reversion to nar+ in a nar1-m nir1-1 strain of ustilago maydis was found to occur under nongrowth conditions by performing the in vivo assay for functional nitrate reductase described by resnick and holliday (1971) who previously demonstrated that nonviable cells may still synthesize normal or near-normal levels of activity. reversion frequencies of a signle gamma-irradiated culture were estimated in two cell populations by different methods: (a) among surviving clones ... | 1976 | 934051 |
| the influence of dna binding protein on the substrate affinities of dna polymerase from ustilago maydis: one polymerase implicated in both dna replication and repair. | the dna polymerase of ustilago maydis is stimulated by a dna binding protein from the same organism. analysis of this stimulation shows that there is an increase in affinity for both substrates of the reaction. the apparent km for deoxynucleoside triphosphates is decreased 3 fold, and that for denatured dna by 4 fold. in both cases the maximum velocity (vmax) is increased 1.2 to 1.4 fold. it is suggested that the variability in the affinity of the enzyme for deoxynucleoside triphosphates mediate ... | 1976 | 934054 |
| [lysine and arginine requirement of "ustilago cynodontis" 4001 yeast-like cells. i. --growth in the presence and in the absence of lysine (author's transl)]. | for optimal growth, the yeast-like cells of ustilago cynodontis 4001 (originating from the mycelium 4001 prototroph forms) require the presence of both arginine and lysine. however, in the absence of lysine, growth does occur, but two exponential growth phases can then be observed: a pseudo-lag phase during which the growth rate is slow, and a second, true exponential phase. the initial od of the culture and the arginine concentration of the medium do not appear to affect the duration of the pse ... | 1976 | 952440 |
| communication through fimbriae during conjugation in a fungus. | | 1976 | 958418 |
| nitrogen-15 nuclear magnetic resonance spectrum of alumichrome. detection by a double resonance fourier transform technique. | | 1976 | 993494 |
| genetic characterization of rec-1, a mutant of ustilago maydis defective in repair and recombination. | | 1976 | 1001898 |
| a novel endonuclease of human cells specific for single-stranded dna. | we have fractionated from human aneuploid cell cultures three different enzyme fractions degrading single-stranded dna. we have purified and characterized one of these dnases; this is an endonuclease working at alkaline ph (around 9.5) and requiring mg2+ for its activity. the enzyme degrades denatured dna over 100 times more efficiently than native dna in optimal conditions. the termini produced by the enzyme have 5'p and 3'oh ends. the enzyme can attack, though at reduced rate, the supertwisted ... | 1976 | 1009931 |
| the effect of some organic substances on the mycelium of the fungus ustilago nuda (jens.) rostr. | research was performed for studying the effect of some organic compounds, considered by many authors as the products ob barley seed metabolism generated after anaerobic seed treatment, on the mycelium of the fungus ustilago nuda (jens.) rostr. the author examined the effectiveness of ethylacohol, acetaldehyde, acetic acid, succinic acid, lactic acid, and hydroquinone in concentrations from 1 m to 10(-6) m, and the effectiveness of extracts from disinfected seeds in doses from 10 g to 0.001 g/l. ... | 1976 | 1037055 |
| mechanisms of resistance to systemic fungicides with special reference to 1,4-oxathiin derivatives. | | 1975 | 1063660 |
| formation of protoplasts from ustilago maydis. | protoplasts of ustilago maydis were obtained by incubating sporidia of the fungus with a combination of helicase and a commercial "onozuka" r-10 enzyme preparation of trichoderma harzianum in the presence of 0.6 m (nh4)2 so4 as an osmotic stabilizer. in the presence of the organic stabilizers sorbitol and sucrose, however, the release of protoplasts was inhibited. combinations of helicase with other lytic enzymes such as cellulase from aspergillus niger, cellulase and hemicellulase from rhizopus ... | 1976 | 1086637 |
| reversible and permanent effects of the carbon sources and various antibiotics on the morphology and metabolic properties of ustilago cynodontis cells. | the effects of various carbon sources and of antibiotics on the morphology of hypha cells of the fungus ustilago cynodontis is described. nonfermentable substrates promote readily reversible yeastlike colonies from hypha cells: all the hypha cells spread on these substrates give rise to yeastlike colonies that revert to the mycelial phenotype when transferred to glucose medium. among the antibiotics tested, chloramphenicol (cap) is found to promote, under certain circumstances, a long-lasting, e ... | 1975 | 1095594 |
| [newer antimycotics. i. derivatives of phenyl-hydrazine (author's transl)]. | the author produced a number of derivatives of phenyl-hydrazine and its analogues, investigated their antimicrobial efficiency in vitro, and discussed the association of chemical structure with the fungistatic effect in the series of phenyl-hydrazine-derivatives. from the author's results it can be concluded that the halogen-substituted phenyl-hydrazines and their n-(acetyl)-derivatives exert a moderate fungistatic effect (tab. 1). in the series of n-aryl-sulphonyl-n'-phenyl-hydrazines only the ... | 1975 | 1099848 |
| specific effects of triarimol on sterol biosynthesis in ustilago maydis. | 1. triarimol (2 mug/ml) severely inhibited ergosterol synthesis in sporidia of ustilago maydis. in control cells ergosterol accounted for 70-85% of the total sterols, in sporidia treated 9.5 h with triarimol the total sterol content was not appreciably reduced; however, ergosterol constituted less than 4% of the sterol fraction. in treated cells 95% of this fraction was composed of 24-methylene-dihydrolanosterol, obtusifoliol and 14alpha-methyl-delta-8,24(28)-ergostadienol. these three sterols a ... | 1975 | 1122314 |
| fungal fimbriae. ii. their role in conjugation in ustilago violacea. | during conjugation in the anther smut fungus ustilago violacea cells of opposite mating type first pair tightly and then develop a conjugation tube or bridge between them. the cells of both mating types are covered in long fine hairs or fimbriae, some of which appear to end in knobs. experiments involving enzyme treatments of the cell surface indicate that these fimbriae do not play an essential role in cell pairing, instead pairing seems to be initiated when one or both mating types produce amo ... | 1975 | 1122428 |
| radiation-sensitive pyrimidine auxotrophs of ustilago maydis. i. isolation and characterization of mutants. | the relationship between uv sensitivity and pyrimidine auxotrophy has been examined. fourteen pyrimidine-requiring mutants have been classified on the basis of genetic complementation and utilization of biosynthetic intermediates and have been assigned to at least four loci. all the mutants studied were sensitive to uv, although the degree of sensitivity varied both between loci and amongst alleles at the same locus. a double mutant strain carrying pyrimidine mutants at two loci was only as sens ... | 1975 | 1134511 |
| radiation-sensitive pyrimidine auxotrophs of ustilago maydis. ii. a study of repair mechanisms and uv recovery in pyr i. | two mutants at the pyr i locus have been used to study the radiation sensitivity of pyrimidine auxotrophs of u. maydis. the mutant pry i-i has a reduced level of thymidine nucleotides, and this is a likely basis of the sensitivity. this strain is able to excise pyrimidine dimers from its dna and is cross-sensitive to gamma-rays and nitrosoguanidine (ng) as well as to uv. a diploid heteroallelic at the pyr i locus was uv-sensitive but not deficient in uv-induced mitotic recombination. the results ... | 1975 | 1134512 |
| differences in germination response of spores of several species of rust and smut fungi to nonanal, 6-methyl-5-hepten-2-one, and related compounds. | | 1975 | 1141529 |
| the isolation and properties of a dna-unwinding protein from ustilago maydis. | | 1975 | 1152048 |
| further evidence for an inducible recombination repair system in ustilago maydis. | | 1975 | 1152856 |
| the excision of pyrimidine dimers from the dna of mutant and wild-type strains of ustilago. | uv-induced pyrimidine dimers were excised from the dna of wild-type and four mutant strains of ustilago maydis. excision was partially dose dependent. the kinetics of excision differed in recombination deficient strains (rec 1 and rec 2) from those found in a recombination proficient radiation-sensitive strain (uvs 3). at fluences above 100 j-m-2 excision was saturated in uvs 3 but not in rec 1 or rec 2. fluences above 300 j-m-2 started to saturate excision in wild-type. pol1-1, a temperature-se ... | 1975 | 1152859 |
| the amino acid sequence of ribonuclease u2 from ustilago sphaerogena. | 1. rnaase (ribonuclease) u2, a purine-specific rnaase, was reduced, aminoethylated and hydrolysed with trypsin, chymotrypsin and thermolysin. on the basis of the analyses of the resulting peptides, the complete amino acid sequence of rnaase u2 was determined, 2. when the sequence was compared with the amino acid sequence of rnaase t1 (ec 3.1.4.8), the following regions were found to be similar in the two enzymes; tyr-pro-his-gln-tyr (38-42) in rnaase u2 and tyr-pro-his-lys-tyr (38-42) in rnaase ... | 1975 | 1156364 |
| evidence for a new kind of regulatory gene controlling expression of genes for morphogenesis during the cell cycle in ustilago violacea. | | 1975 | 1183810 |
| 15n nuclear magnetic resonance of living cells. | | 1975 | 1186871 |
| sporulation by ustilago enneapogonis in axenic culture. | | 1975 | 1214837 |
| dna polymerase of ustilago maydis: partial characterization of the enzyme and a pol 1 mutation. | the major dna polymerase activity of wild-type u. maydis has been extensively purified. it possesses a molecular weight of about 150,000 daltons and appears to require a dna primer with a 3'-hydroxyl terminus as well as a template. the polymerase activity has also been purified from the pol 1-1 strain, which is temperature sensitive fro growth and dna synthesis, and which at the restrictive temperature contains only 10-25% levels of the dna polymerase activity obtained from wild-type strains. it ... | 1975 | 1221304 |
| the disulfide bridges of ribonuclease u2 from ustilago sphaerogena. | rnase u2 was partially hydrolyzed with chymotrypsin [ec 3.4.21.1] and sulfuric acid, and in each case the resulting peptides were separated by gel filtration, ion exchange column chromatography and paper electrophoresis. from the results of amino acid analysis of cystine-containing peptides and their oxidized components, the three disulfide bridges were located between the cystine residues at positions 1 and 53, 9 and 112, and 54 and 95. | 1975 | 1225902 |
| some biochemical changes in young barley plants, due to the vitavax disinfection of seeds against ustilago nuda (jens.) rostr. | | 1975 | 1242263 |
| suppression of the killer phenotype in ustilago maydis. | nineteen sensitive cell lines of u. maydis were crossed with three killer strains and sample progenies were screened for killer segregation patterns. crosses involving 11 lines gave killer frequencies ranging from 71%-100% of the progeny and 4:0 segregations in tetrads. segregations in some crosses involving each of the remaining 8 lines gave killer frequencies from 0%-58% and mixed tetrads containing both non-killer and killer meiotic products. many of the killers were unstable on further cultu ... | 1976 | 1269912 |
| the a mating type locus of u. maydis specifies cell signaling components. | the a mating type locus of the phytopathogenic fungus u. maydis controls fusion of haploid cells and filamentous growth of the dikaryotic mycelium. the a locus exists in two alleles, termed a1 and a2, which are defined by nonhomologous dna regions comprising 4.5 kb for a1 and 8 kb for a2, flanked by identical sequences. based on functional assays, mutants, and sequencing, we demonstrate that the mating type in each allele is determined by a set of two genes. one encodes a precursor for a lipopep ... | 1992 | 1310895 |
| in vitro analysis of a type i dna topoisomerase activity from cultured tobacco cells. | the role of dna topoisomerases in plant cell metabolism is currently under investigation in our laboratory. using a purified type i topoisomerase from cultured tobacco, we have carried out a biochemical characterization of enzymatic behavior. the enzyme relaxes negatively supercoiled dna in the presence of mgcl2, and to a lesser extent in the presence of kcl. phosphorylation of the topoisomerase does not influence its activity and it is not stimulated by the presence of histones h1 or h5. the en ... | 1992 | 1320423 |
| a study of the aeromycoflora of cádiz: relationship to anthropogenic activity. | we describe a quantitative and qualitative study of the fungal spores found in the air of cádiz during 1989 using a cour-type trap. the results of this study can be extrapolated to other coastal cities of southern europe with a mediterranean climate. the spores identified have been classified into 25 taxonomic categories. the most abundant were cladosporium, chaetomium and ustilago, and the most frequent, in addition to those mentioned, were alternaria, ascophyta and venturia. the great abundanc ... | 1992 | 1342902 |
| transmission of mitochondrial dna in ustilago violacea. | mitochondrial dna (mtdna) restriction fragment length polymorphisms (rflps) were used as genetic markers for following mitochondrial transmission in the basidiomycete ustilago violacea. yeast-like cells of opposite mating types (a1 and a2) were mated on 2% water agar and were treated with alpha-tocopherol to induce formation of dikaryotic hyphae. upon depletion of the alpha-tocopherol, the hyphae budded off haploid cells with parental nuclear genotypes. these cells were examined for mitochondria ... | 1992 | 1358468 |
| homeodomains and regulation of sexual development in basidiomycetes. | | 1992 | 1369739 |
| ustilago maydis, the delightful blight. | recent studies of the corn smut fungus life cycle and its regulation by two mating type loci and other genes provide a cornucopia of challenges in cell biology, genetics and protein structure. the fungus can exist in two states: nonpathogenic and pathogenic. the change from one state to the other is accompanied by a change in morphology (yeast-like to filamentous) and growth properties (saprophytic to parasitic). | 1992 | 1369743 |
| a single amino-acid change in the iron-sulphur protein subunit of succinate dehydrogenase confers resistance to carboxin in ustilago maydis. | the sequence of an allele encoding the iron-sulphur protein (ip) subunit of succinate dehydrogenase (sdh) was determined following pcr amplification of genomic dna from a carboxin (cbx)-sensitive ustilago maydis strain. comparison of this sequence with that of the ip allele from a cbx-resistant strain (ipr) revealed a two-base difference between the sequences. this mutation led to the substitution of a leucine residue for a histidine residue within the third cysteine-rich cluster of the deduced ... | 1992 | 1423716 |
| techniques for studying photoprotective function of carotenoid pigments. | | 1992 | 1435316 |
| a biological assay for the detection of myrothecium spp. produced macrocyclic trichothecenes. | a rapid, inexpensive bioassay to detect myrothecium spp.-produced macrocyclic trichothecenes was developed. media containing myrothecium isolates were inoculated with chlorella vulgaris, ustilago maydis and trichoderma viride. based on width of the inhibition zone, isolates could be classified as highly toxigenic, non-toxigenic and intermediate. whereas, c. vulgaris and u. maydis showed significant differences in their response to toxigenic and non-toxigenic isolates, t. viride did not. producti ... | 1992 | 1435958 |
| cloning and molecular characterization of the glyceraldehyde-3-phosphate dehydrogenase-encoding gene and cdna from the plant pathogenic fungus glomerella cingulata. | the glyceraldehyde-3-phosphate dehydrogenase gene (gpda) has been identified from a genomic dna library prepared from the plant pathogenic fungus glomerella cingulata. nucleotide sequence data revealed that this gene codes for a putative 338-amino-acid protein encoded by two exons of 129 and 885 bp, separated by an intron 216 bp long. the 5' leader sequence is also spliced by an intron of 156 bp. a cdna clone was prepared using the polymerase chain reaction, the sequence of which was used to con ... | 1992 | 1452034 |
| the gene coding for small ribosomal subunit rna in the basidiomycete ustilago maydis contains a group i intron. | the nucleotide sequence of the gene coding for small ribosomal subunit rna in the basidiomycete ustilago maydis was determined. it revealed the presence of a group i intron with a length of 411 nucleotides. this is the third occurrence of such an intron discovered in a small subunit rrna gene encoded by a eukaryotic nuclear genome. the other two occurrences are in pneumocystis carinii, a fungus of uncertain taxonomic status, and ankistrodesmus stipitatus, a green alga. the nucleotides of the con ... | 1992 | 1561081 |
| specificity of ustilago maydis killer proteins. | bacteria and fungi were tested for sensitivity to ustilago maydis killer strains carrying virus-like particles. various species taxonomically related to u. maydis were sensitive. | 1975 | 1190764 |
| inheritance of killer phenotypes and double-stranded rna in ustilago maydis. | three different killer specificities in u. maydis are inherited cytoplasmically and transmitted by cell fusion. each killer generates low frequencies of specifically immune forms in crosses with sensitive strains. the properties of immunity to each killer are also inherited cytoplasmically and transmitted by cell fusion. killer strains carry virus-like particles about 41 nm in diameter. each killer possesses distinct double-stranded rna components that range in molecular weight from 0.46 x 10(6) ... | 1976 | 1061159 |
| induced mutagenesis in ustilago maydis. i. isolation and characterization of a radiation-revertible allele of the structural gene for nitrate reductase. | a uv-revertible mutant of the nar1 structural gene for nitrate reductase was isolated in wild-type (nar+ nir+) ustilago maydis. it proved to be vigorously revertible by gamma rays as well. genetic analysis revealed that the strain carried a single, nonleaky, recessive allele (nar1-m) with an unusually high spontaneous reversion rate (approximately 3 x 10(-5)/div.). reliable reversion frequencies were determined with a special agar medium that reduced the normally high level of residual growth ob ... | 1976 | 934050 |
| a dna polymerase from ustilago maydis. evidence of proof-reading by the associated 3' leads to 5' deoxyribonuclease activity. | the 3' leads to 5' deoxyribonuclease activity associated with an ustilago maydis dna polymerase hydrolysed non-complementary 3'-primer termini about 12 times more rapidly than complementary termini. an analysis of its substrate specificity suggested that, although it was unable to hydrolyse fully single-stranded polynucleotides, it could hydrolyse such regions less than about four nucleotides in length covalently bound to a primer molecule which was base-paired to a complementary template strand ... | 1977 | 891548 |
| lipid composition of strains of the fungus ustilago zeae (beckm.) differing as regards their hybridization type. | the composition of the intracellular lipids was studied in four strains of ustilago zeae differing as regards their hybridization type. in all strains, irrespective of the hybridization type, the bulk of the lipids are formed during the first three days of growth and constitute 43.2--55.7% of the weight of the dry cells. it was established that the total lipid fraction is composed of: phospholipids + monoglycerides, sterols, free fatty acids, diglycerides and sterol esters. the qualitative compo ... | 1978 | 753397 |
| nuclease activity associated with the ustilago maydis virus induced killer proteins. | an in vitro nuclease activity was found to be associated with the purified killer proteins of ustilago maydis. the proteins are effective against single stranded rna, single and double stranded dna. endonucleolytic activity was confirmed by cleavage of circular molecules of 0x174 and pm2. double stranded rna did not appear to serve as a substrate. | 1979 | 493119 |
| heparin-mediated transformation of escherichia coli with ustilago maydis dna. | the inhibiton of escherichia coli transformation caused by simple preparations of ustilago maydis plasmid and genomic dna can be efficiently overcome by the use of the linear polyanion heparin. techniques using heparin have been derived that should facilitate the production and isolation of plasmids passed through ustilago maydis and may be of benefit in other systems where similar inhibitory phenomena or low transformability are observed. | 1991 | 1878203 |
| isolation, characterization and sequence of a gene conferring resistance to the systemic fungicide carboxin from the maize smut pathogen, ustilago maydis. | a gene which confers resistance to the systemic fungicide carboxin (cbx) has been isolated from the maize pathogen, ustilago maydis, by transferring a plasmid gene library from a cbx-resistant mutant strain into a sensitive strain and selecting for expression of the resistance gene. five plasmids, rescued from transformants which exhibited enhanced resistance to cbx, were shown to have dna inserts with common restriction enzyme fragments. all the plasmids transformed a sensitive u. maydis strain ... | 1991 | 1879000 |
| ethoxyformylation of ribonuclease u2 form ustilago sphaerogena. | rnase u2 was inactivated by incubation with ethoxyformic anhydride at ph 6.0 and ph 4.5. the absorbance of the rnase u2 increased at around 250 nm and decreased at around 280 nm. the inactivation occurred in parallel with the amount of modified histidine and plots of the relationship between the remaining activity and the modified histidine suggested that the modification of one of the two histidine residues totally inactivated the enzyme. the inactivated enzyme rnase u2 was reactivated by a ... | 1975 | 238967 |
| cloning the rec1 gene of ustilago maydis. | the rec1 gene of ustilago maydis plays a key role in homologous recombination and the repair of damaged dna. in order to understand the nature and functions of the gene product, the gene has been cloned by functional complementation. a 3.8 kb cloned fragment complements the pleiotropic mitotic phenotype of different rec1 alleles. it does not complement the uv sensitivity of two other sensitive mutants. disruption of the chromosomal copy of the 1.566 kb open reading frame within this fragment rep ... | 1991 | 1934111 |
| the b alleles of u. maydis, whose combinations program pathogenic development, code for polypeptides containing a homeodomain-related motif. | u. maydis is a fungal pathogen of corn with two forms: one is yeast-like and nonpathogenic; the other is filamentous and pathogenic. the b locus, with 25 different alleles, regulates this dimorphism: any combination of two different alleles triggers pathogenic development, whereas the presence of identical alleles results in the yeast-like form. we have cloned four b alleles (b1, b2, b3, and b4) and show that the b locus contains a single open reading frame (orf) of 410 amino acids with a variab ... | 1990 | 1967554 |
| a protein from ustilago which forms an acid-soluble complex with deoxyribonucleic acid. | a protein which can render dna largely acid-soluble has been purified 1600-fold from high salt extracts of ustilago maydis. the activity is unusual in that substrate dna is not made acid-soluble through hydrolysis to small oligomers. rather, the protein appears to bind to dna to form a complex which itself is acid-soluble. the activity of conversion of dna to an acid-soluble form is cold-labile, but the inactivation by cold is reversible by brief heat treatment. divalent cations stimulate the ac ... | 1975 | 235535 |
| the role of ferrichrome reductase in iron metabolism of ustilago sphaerogena. | ferrichrome, the ferric ionophore for ustilago sphaerogena, can serve as a source of iron for the enzyme ferrochelatase (protoheme ferrolyase, ec 4.99.1.1) in this organism, but only after enzymatic removal of the iron from its carrier. u. sphaerogena contains a specific ferrichrome reductase (nadh:ferrichrome oxidoreductase) which catalyzes cellular dissociation of the complex by reduction of the metal to the ferrous state. a spectrophotometric assay was developed based on trapping of the ferro ... | 1979 | 224934 |
| [dimorphism in "ustilago cynodontis". ii--glucidic metabolism (author's transl)]. | the glucidic metabolism has been studied in four strains of ustilago cynodontis. two of them--m1 and m7--are mycelial strains, the two others --l1 and l7--being yeast like are respectively issued from m1 and m7. the results obtained show that the choice between the different glucidic catabolism pathways takes place at the phosphofructokinase level. when the phosphofructokinase is lacking (m1) the catabolism occurs via the pentose phosphate cycle followed by the last glycolytic reactions (between ... | 1976 | 135525 |
| the a mating-type alleles of ustilago maydis are idiomorphs. | two unlinked incompatibility loci, a and b, control mating, pathogenicity, and sexual development in ustilago maydis, a fungal pathogen of corn. fusion of nonpathogenic haploid cells occurs when alleles of the a locus differ; fusion products that differ at the b locus will be pathogenic and complete sexual development. the two alleles of the a locus have been cloned. the a2 allele was isolated by exploiting the close linkage of the a locus to the genetic marker pan1. several cosmids from a clona ... | 1991 | 2055462 |
| the promoter of the glucoamylase-encoding gene of aspergillus niger functions in ustilago maydis. | promoter sequences from the aspergillus niger glucoamylase-encoding gene (glaa) were linked to the bacterial hygromycin (hy) phosphotransferase-encoding gene (hph) and this chimeric marker was used to select hy-resistant (hyr) ustilago maydis transformants. this is an example of an ascomycete promoter functioning in a basidiomycete. hyr transformants varied with respect to copy number of integrated vector, mitotic stability, and tolerance to hy. only 216 bp of glaa promoter sequence is required ... | 1990 | 2112106 |
| the kinetics of the active and de-energized transport of o-methyl glucose in ustilago maydis. | the kinetics of the uptake and efflux of 3-o-methyl-glucose in sporidia of ustilago maydis were measured, both in active cells and in cells whose metabolic activity had been inhibited by azide and iodoacetate. the de-energized transport system proved to be carrier mediated with apparent affinity constants 13 +/- 2 mm outside (ko) and 18 +/- 2 mm inside (k1). the apparent maximum rate constants for the same system were 0.66 +/- 0.05 mmol/1 cell water per min for uptake (v+) and 0.53 +/- 0.04 mmol ... | 1978 | 32904 |
| immunity and resistance to the kp6 toxin of ustilago maydis. | the kp6 toxin of ustilago maydis, encoded by segmented double-stranded (ds) rna viruses, is lethal to sensitive strains of the same species and related species. the toxin consists of two polypeptides, alpha and beta, synthesized as a single preprotoxin, which are not covalently linked. neither polypeptide alone is toxic, but killer activity can be restored by in vitro and in vivo complementation. killer-secreting strains are resistant to the toxin they produce. resistance is conferred by a singl ... | 1992 | 1620096 |
| the b mating-type locus of ustilago maydis contains variable and constant regions. | the b locus of the phytopathogenic fungus ustilago maydis encodes a multiallelic recognition function that controls the ability of the fungus to form a dikaryon and complete the sexual stage of the life cycle. the b locus has at least 25 alleles and any combination of two different alleles, brought together by mating between haploid cells, allows the fungus to cause disease and undergo sexual development within the plant. an open reading frame of 410 amino acids has been shown to specify a polyp ... | 1990 | 2227416 |
| isolation and characterization of a ustilago maydis glyceraldehyde-3-phosphate dehydrogenase-encoding gene. | the complete nucleotide sequence of the glyceraldehyde-3-phosphate dehydrogenase gene from the corn smut fungus ustilago maydis is reported. the gene encodes a 337-amino acid protein, parts of which show sequence identity to corresponding regions of gapdh-encoding genes from other organisms. a single, putative 407-bp intron interrupts the tenth codon. codon usage is highly biased for codons ending in cytosine. | 1990 | 2227419 |
| microbial genetics. sexual identity and smut. | | 1992 | 1574124 |
| individual patterns of immediate skin reactivity to mold extracts. | one hundred atopic patients were skin tested intradermally over a 2-year period with 30 different mold extracts. subjects were monitored for immediate reactions. data suggest that to evaluate mold sensitivity in atopic patients one must use multiple mold extracts. | 1990 | 2256573 |
| isolation of the rec2 gene controlling recombination in ustilago maydis. | the rec2 mutant of ustilago maydis is defective in dna repair, induced allelic recombination, and meiosis. we cloned the rec2 gene by complementing the radiation-sensitive phenotype of the mutant using a genomic dna library. the transcript of the rec2 gene was identified as a 2.8-kb damage-inducible rna. | 1990 | 2269439 |
| pathways of transformation in ustilago maydis determined by dna conformation. | ustilago maydis was transformed by plasmids bearing a cloned, selectable gene but lacking an autonomously replicating sequence. transformation was primarily through integration at nonhomologous loci when the plasmid dna was circular. when the dna was made linear by cleavage within the cloned gene, the spectrum of integration events shifted from random to targeted recombination at the resident chromosomal allele. in a large fraction of the transformants obtained using linear dna, the plasmid dna ... | 1990 | 2323553 |
| from interferon induction to fungal viruses. | viruses of fungi (mycoviruses) were first discovered in diseased mushrooms. however the finding that the antiviral and interferon-inducing activities of extracts of apparently healthy isolates of a number of penicillium species were due to the presence of double-stranded (ds) rna arising from mycovirus infections sparked off an explosion of interest in what has now become a distinct area of virology. two families of dsrna mycoviruses are now established: the totiviridae and the partitiviridae wh ... | 1988 | 2462507 |
| the a and b loci of ustilago maydis hybridize with dna sequences from other smut fungi. | the smut fungi are obligately parasitic during the sexual phase of their life cycle, and the mating-type genes of these fungi play key roles in both sexual development and pathogenicity. among species of smut fungi it is common to find a bipolar mating system in which one locus with two alternate alleles is believed to control cell fusion and establishment of the infectious cell type. alternatively, several species have a tetrapolar mating system in which two different genetic loci, one of which ... | 1992 | 1515669 |
| characterization of siderophores from ustilago maydis. | two siderophores, ferrichrome and ferrichrome a, were found in cultures of ustilago maydis (dc) corda. both siderophores were found intracellularly and extracellularly. their authenticity was confirmed by thin layer chromatography, hplc, uv-visible spectrometry, paper electrophoresis, amino acid analysis, nmr and fast atom bombardment mass spectroscopy. regulation of siderophore production by iron was examined. repression of biosynthesis of extracellular siderophores occurred at 10(-5) m iron. f ... | 1989 | 2531844 |
| the human recombination strand exchange process. | a mechanism for the initiation of general recombination that involves the formation of left-handed z-dna heteroduplex segments adjacent to right-handed b-dna heteroduplex segments is discussed. the paranemic nature of this initiation structure allows for homology recognition in the absence of strand cleavage. this model suggests that proteins catalyzing recombination initiation via the formation of paranemic joint should in some capacity recognize z-dna. other studies have shown that both the re ... | 1989 | 2591739 |
| characterization of the termini of linear plasmids from nectria haematococca and their use in construction of an autonomously replicating transformation vector. | the mitochondria of isolate fs37 from nectria haematococca mating population i (fusarium solani f. sp. cucurbitae) contain two linear plasmids, pfsc1 and pfsc2, of 9.2 and 8.3 kbp, respectively. evidence for a protein blocking the 5' termini of these plasmids was obtained from exonuclease digestion experiments. a single protein band with an apparent mr of 80 k was labeled when the dna-protein complex of either plasmid was reacted with [125i] bolton-hunter reagent and then digested with dnase i. ... | 1989 | 2598274 |
| nucleotide sequence of the rec1 gene of ustilago maydis. | | 1989 | 2602156 |
| the influence of the ustilago maydis rec1 gene on plasmid-chromosome recombination. | the rec1 gene of u. maydis has an important but ill-defined role in dna recombination and repair. we have examined its role in plasmid-chromosome recombination. plasmid dna was linearized at various locations with respect to the cloned u. maydis pyr3 gene and introduced into cells by transformation. chromosomal integration and repair by an homologous cross-over with plasmid containing a double-strand break or gap in the pyr3 gene was markedly reduced in the absence of the rec1 gene product. homo ... | 1992 | 1473180 |
| the a locus governs cytoduction in ustilago maydis. | we have developed a cytoduction assay to measure cell fusion quantitatively in the basidiomycete corn smut fungus ustilago maydis. this assay employs a mutation conferring resistance to oligomycin that exhibits non-mendelian inheritance and presumably affects the mitochondrial genome. after auxotrophic olir cells are mixed with prototrophic olis cells, prototrophic olir cells can be detected at a significant frequency after several hours of incubation, reaching a maximum of 10% of the total prot ... | 1992 | 1447150 |
| transformation in fungi. | transformation with exogenous deoxyribonucleic acid (dna) now appears to be possible with all fungal species, or at least all that can be grown in culture. this field of research is at present dominated by saccharomyces cerevisiae and two filamentous members of the class ascomycetes, aspergillus nidulans and neurospora crassa, with substantial contributions also from fission yeast (schizosaccharomyces pombe) and another filamentous member of the class ascomycetes, podospora anserina. however, tr ... | 1989 | 2651864 |
| neutralizing monoclonal antibodies against alpha and beta subunits of the ustilago maydis virus encoded toxin. | the toxins secreted by ustilago maydis are encoded by dsrna viruses. the kp6 toxin encoded by subtype p6 consists of two polypeptides alpha and beta, which are not covalently bound. neutralizing monoclonal antibodies (moabs) were raised against each subunit. some of the anti-beta moabs identify different epitopes in the antigen. the moabs were used to affinity purify alpha and beta polypeptides from culture media and to detect the precursor of the mature toxin. | 1992 | 1413542 |
| a very small viral double-stranded rna. | umv is a double-stranded rna (dsrna) virus of the corn fungal pathogen ustilago maydis. umv has no infectious cycle. some umv subtypes have viral dsrnas encoding secreted toxins that kill sensitive cells of the same species and related species. there are three viral subtypes, p1, p4 and p6, which differ in the specificity of their secreted killer toxins. each has three size classes of dsrna: h (heavy), m (medium) and l (light). the l segments of umv are unique in being derived from one end of th ... | 1989 | 2718392 |
| the molecular biology of pathogenesis in ustilago maydis. | | 1992 | 1368277 |
| purification and molecular properties of the toxin coded by ustilago maydis virus p4. | the toxin from the p4 strain of ustilago maydis was purified and characterized using a series of gel-filtration and ion-exchange columns. the apparent molecular weight of the purified toxin was estimated from gel electrophoresis to be 11.3 kd in the presence of 2-mercaptoethanol and 10.3 kd in the absence of 2-mercaptoethanol. amino acid analysis indicated 12% basic amino acids, 14% acidic amino acids and 16% glycine. the toxin was also stable to filtration and repeated freezing at -20 degrees c ... | 1989 | 2757636 |
| rapid isolation of double stranded rna segments from disulphide crosslinked polyacrylamide gels. | a simple method was developed to isolate dsrna segments from disulphide crosslinked polyacrylamide gels. the dsrna preparations from the p4 killer virus strain 77 of ustilago maydis containing 7 genomic segments with molecular sizes ranging from 0.36 to 6.7 kbp, the 20 kbp dsrna associated with the '447' cytoplasmic male sterility in vicia faba and the 23 kbp genomic dsrna of citrus tristeza virus (ctv) were separated on disulphide crosslinked polyacrylamide gels. after uv visualisation, the dsr ... | 1989 | 2760164 |
| introduction and maintenance of prokaryotic dna in ustilago violacea. | a strain of the basidiomycete, ustilago violacea, was transformed with a prokaryotic plasmid, pmp4-1, which confers resistance to neomycin. u. violacea transformants were selected at a frequency of 5 per microgram pmp4-1 dna. such transformants were at least 8-fold more resistant to neomycin than was the untransformed recipient u. violacea. enzyme activity associated with the neomycin resistance gene was also found in the transformants. southern dna-dna hybridization detected pmp4-1-derived sequ ... | 1990 | 1366759 |
| detection of killer-independent dsrna plasmids in ustilago maydis by a simple and rapid method of extraction of dsrna. | a novel method for efficient and rapid isolation of dsrna molecules was developed. the dsrna content of ustilago maydis was reexamined; two distinct dsrna classes were identified. class i includes the dsrna segments reported earlier for u. maydis virus systems and class ii includes unencapsidated dsrna molecules that were barely detected by the conventional extraction methods despite their high titer. segments of the class ii, some of which are reported for the first time, were further character ... | 1989 | 2780894 |
| an aerobiological survey of allergens in al khobar, saudi arabia. | a nationwide aerobiologic study is in progress in saudi arabia using burkard 7-day volumetric spore traps to determine the major airborne allergens and their seasonal patterns. eights months readings have been completed at al-khobar, an important coastal city on the arabian gulf. pollen levels showed a double season. an autumnal peak reached its maximum in october rising sharply from the low summer values before falling during the short winter then rising again in springtime. both local and impo ... | 1989 | 2789674 |